Behind Security Center is an engine that continuously monitors the configuration status of these security services and informs users’ of their status. Each service’s status is checked against the preferred configuration settings that are specified in the Security Center configuration dialog box, which is shown in Figure 1. For example, the Security Center verifies that Windows Firewall, Automatic Updates, and real-time virus scanning are enabled and that the virus protection signature files are up-to-date. If Security Center finds that a service isn’t operating as specified in the Security Center configuration dialog box, it alerts the user by displaying a red icon in the user’s taskbar (as shown in Figure 2) or displays an alert message on the user’s desktop.

Users can modify the way Security Center notifies them of problems by clicking the Change the way Security Center alerts me button that’s located in the left pane of the Security Center dialog box. From the resulting Windows Security Center dialog box, users can disable the Security Center notifications, enable only user taskbar notifications, or enable only notification messages on the user’s desktop.

Security Center is enabled by default on Vista and XP SP2 systems that aren’t joined to a Windows domain. For domain-joined machines, administrators can enable and disable Security Center via the Turn on Security Center (Domain PCs only) Group Policy Object (GPO) setting that’s located in the Computer Configuration\Administrative Templates\Windows Components\Security Center GPO container.